Olive Stone Flour Research Articles

Production of functional crackers based on non-conventional flours. Study of the physicochemical and sensory properties

Crackers are popular snacks that can include functional ingredients in order to make products of higher nutritional value. The effect of partial replacement of wheat flour with barley, grape seed, olive stone, lupin and chickpea flour (10–50%) on the physicochemical (texture, color, and moisture) and sensory aspects of crackers was studied. Texture remained unaffected from substitution of wheat flour in all cases except for high (30%) substitution with olive stone flour, which led to softer crackers (43% and 52% reductions in hardness and toughness, respectively). All levels of wheat substitution resulted to darker color of crackers (L* values declined between 1.4–60%). Overall, color was predominately affected by the level of flour used as well as flour type. Higher levels of substitution exerted a stronger impact. The sensorial perception of crackers was negatively affected by the addition of grape seed and olive stone flours, while it was positively affected by pulse flours. The results showed that functional flours can be utilized in cracker formulations as alternatives to wheat flour, however, sensory acceptability depends on flour type and level of substitution.

Life Cycle Assessment of Olive Pomace as a Reinforcement in Polypropylene and Polyethylene Biocomposite Materials: A New Perspective for the Valorization of This Agricultural By-Product

The main environmental impact of olive oil production is the disposal of residues such as pomace and water vegetation. During the olive oil extraction process, the olive stone is milled and discharged within the olive pomace. However, olive stone flour can be valorized as filler for polymeric composites. A life cycle assessment of the olive pomace valorization was carried out by focusing on the manufacturing process of a biocomposite made of two different thermoplastic matrices, i.e., polyethylene and polypropylene. The functional unit is the production of 1 m2 of a lath made of an olive pomace-based biocomposite. The analysis was carried out with the SimaPro PhD 9.1.1.1 software, and the database used for the modeling was Ecoinvent 3.6. The obtained results reveal that the hotspot of the whole process is the twin-screw compounding of the olive stone fraction, with the polymeric matrix and coupling agent, and that human health is the most affected damage category. It represents 89% for both scenarios studied: olive stone fraction/polypropylene (OSF/PP) and olive stone fraction/polyethylene (OSF/PE). Further research directions include the use of biosourced polymer matrices, which could reduce the impact of olive pomace-based composite manufacturing.

Nonisothermal crystallization of poly(l-lactide) in poly(l-lactide)/olive stone flour composites

Nonisothermal crystallization of poly(l-lactide) in poly(l-lactide)/olive stone flour (PLLA/OSF) composites was studied applying differential scanning calorimetry (DSC). The analysis was carried out during cooling of the melt at different and constant rates. The kinetic parameters of the crystallization were determined by the Avrami, Ozawa and Mo methods. The Avrami analysis revealed the existence of two mechanisms of nonisothermal crystallization in all samples. The Ozawa and Mo methods failed to successfully describe the crystallization behaviour of PLLA with or without OSF. The effective activation energy of nonisothermal crystallization was estimated with the Friedman method. The kinetic analysis using the Friedman method showed the complexity of the crystallization process. The results of structural investigation shown that OSF has a low influence on the interplanetary distance of PLLA crystal phase. The crystallite size of PLLA decreases with increasing cooling rates and the conditions for the growth of the lamellar structure is more suitable at the lower cooling rate.

Thermal Insulation Properties of Organic and Inorganic Material in Clay Brick - A Review

Pore forming agent is widely used in clay brick making process whether originally organics or inorganics materials which can improve thermal insulation facing global warming issue. Many researchers trigged to discover the thermal insulation materials since the past decade due to responsibility to develop a comfort living demand for heating or cooling. This paper review on different types of thermal inorganic and organic insulation materials added into a clay brick to improve the thermal insulation properties. The scope of these reviews lies to the materials of; paper residue, rice husk, rice husk ash, olive stone flour, wheat straw, perlite, cigarette butt, vermiculite, waste marble powder and waste glass sludge. The discussions are made based on the properties of organic and inorganic materials used in improving the thermal insulation in clay brick. Hence, a throughout review of the composition and properties of brick and various factor related to manufacturing process is highly required for better standardization of clay bricks. A better understanding of different wastes incorporating clay brick utilize of various mining and industrial as well as achieving the goal of sustainable development.

Modeling of the thermal and mechanical properties of clay ceramics incorporating organic additives

This paper presents the results of a combined experimental and theoretical study on a clay ceramic used for building applications. The thermal and mechanical properties of the clay ceramic were improved by addition of organic additives. The organic additives consisted of Olive Stone Flour (OSF), with round-shape particles of 55µm, and Wheat Straw (WS), with 877µm particles in the form of fibers. It was found that the combustion of OSF and WS resulted in a porosity formation during the firing process. The morphology of these pores corresponded to that of the organic additives. Therefore, the addition of small OSF particles decreased the median pore size of the clay ceramic. It improved the mechanical strength of the clay ceramic by 12% for an 8wt% addition of OSF. On the other hand, the WS fibers increased the clay ceramic anisotropy. This resulted in a 41% improvement of the thermal conductivity using an 8wt% addition of WS. Finally, a model was developed from these experimental results to predict the thermal conductivity and the mechanical strength of the clay ceramic with other organic additives. They were predicted from the parameters of the organic additives (i.e., true density, swelling degree, particle size distribution, particle shape factor). The predictions indicated that the thermal conductivity is improved by 50% with a 25% improvement of the mechanical strength using small organic fibers, which is a step forward in the development of fired clay bricks that can be used for both insulation and structure purposes in building applications.

Development of porous fired clay bricks with bio-based additives: Study of the environmental impacts by Life Cycle Assessment (LCA)

The incorporation of bio-based pore-forming agents, from either agricultural (wheat straw – WS and olive stone flour – OSF) or chemical (glycerol carbonate – GC and dimethyl carbonate – DMC) origins, into clay formulations, has been investigated. Fire clay porous tablets have been manufactured at laboratory scale and characterized through physical, mechanical and thermal properties. An increase of 7.2% of the porosity correlated to a decrease of 7.0% of the thermal conductivity was measured for the best samples.The environmental impacts of these formulations have also been examined through a Life Cycle Assessment (LCA) using the ReCiPe v1.10 method. It was noticed that the incorporation of pore-forming agents led a decrease of about 15–20% of all the studied impact categories.The advantage of the use of bio-based additives in clay bricks was then confirmed from both performance (lighter material with a better thermal insulation) and environmental points of view.

The impact of the particle shape of organic additives on the anisotropy of a clay ceramic and its thermal and mechanical properties

This research investigated the impact of the particle shape of organic additives on the anisotropy of a clay ceramic and its thermal and mechanical properties. The impact of the particle shape was elucidated by addition in the clay ceramic mixture of Olive Stone Flour (OSF) in the form of powder and Wheat Straw (WS) in the form of fibers. The OSF powder reduced the clay ceramic anisotropy with a formation of round shape pores during the firing process. The flexural strength of the clay ceramic was improved by 13% in case of an 8wt% addition of OSF. On the other hand, the WS fibers increased the anisotropy by the formation of orientated pores along the extrusion plane. The thermal diffusivity of the clay ceramic was improved by 41% in the direction of the thermal gradient of the walls in case of an 8wt% addition of WS. Hence, this study proved the particle shape of the organic additives as a useful parameter to control the anisotropy of clay ceramics and improve their thermal and mechanical properties.

Properties of fired clay bricks with incorporated biomasses: Cases of Olive Stone Flour and Wheat Straw residues

In recent years, interest in green building materials and the valorisation of by-products from multiple industries has been increasing. As the brick industry allows various compounds to be added during the mixing procedure, much research has been conducted to highlight the impact of additions on fired clay bricks. This paper examines the significance of adding organic matter coming from agricultural solid waste (Olive Stone Flour, OSF, and Wheat Straw, WS residues) to improve thermal performance while maintaining load bearing capacity. The results show a decreasing bulk density for mixtures containing OSF, ranging from −6% to −19% compared to clay alone, and for WS mixtures, where the bulk density reduction is from −4% to −20%. Total porosity increases by 5–56% for OSF, and by 7–67% for WS, implying lower thermal conductivity for WS (−23% relative to clay alone) compared to OSF (−16%) when 5%.wt is incorporated. The compressive strength, for 5%.wt WS and 5%.wt OSF is −52% and −31% respectively. There is a significant positive correlation between the increasing amount of organic matter and the porosity. The most striking result to emerge from the data is that, for the same %.wt, WS creates higher total pore volume than OSF owing to the difference of grain size distribution. Consequently the pore size distribution of new materials containing OSF is more structured and leads to a better compressive strength than WS.

Fired clay bricks using agricultural biomass wastes: Study and characterization

The main objective of this study is to investigate the effects of the incorporation of renewable pore-forming agents on the properties of fired bricks. Different additives have been studied (wheat straw, sunflower seed cake and olive stone flour) at different grinding and incorporation rate.Physical properties such as linear shrinkage, loss on ignition, bulk porosity, water absorption and bulk density have been measured. Mechanical and thermal performances have also been characterized. The incorporation of 4wt.% of sunflower seed cake, with the lowest grinding, leads to the best compromise between mechanical and thermal results compared to the reference brick.

Olive stones flour as reinforcement in polypropylene composites: A step forward in the valorization of the solid waste from the olive oil industry

The usefulness of olive stone flour (OSF) from the solid residue of the olive oil extraction as a reinforcement for the preparation of a cost-effective polypropylene-based composite was investigated. The lignocellulosic filler consisted of acicular particles with a broad size distribution ranging from about 50 to 400μm, and is composed of lignin, hemicelluloses, and cellulose. Composites with filler loading up to 70wt% were prepared using a melt processing and injection molding. The evolution of the mechanical performance, impact properties, and water absorbance of the composites as a function of the filler content were investigated. The addition of a maleated polypropylene (MAPP) coupling agent at a level of 5%, with respect to the filler, was shown to be essential in bringing about a reinforcing effect. A steady increase in the modulus along with a preservation in the tensile strength was observed up to a content of 60% OSF. The obtained results have confirmed the viability of OSF as cheap reinforcing filler for the PP matrix; thus, opening new perspectives for the use of this agricultural by-product.

Polypropylene composites based on lignocellulosic fillers: How the filler morphology affects the composite properties

In this research, composite materials were made from wood flour (WF) or olive stone flour (OSF) as reinforcement, polypropylene (PP) as polymer matrix, and maleated polypropylene (MAPP) as coupling agent, by using injection molding. The effects of the filler loading and coupling agent on the physical properties of the composites, in terms of tensile and impact strength, water absorption and wear resistance were studied. The macromechanical properties were explained by the morphological features of the reinforcements. Composites containing coupling agents exhibited the best mechanical properties, and reduced the negative impacts of water absorption. The difference in the morphology of the two lignocellulosic fillers was found to be a key factor controlling the properties of the composites and the evolution of their properties against water absorption.

Polyvinyl chloride composites filled with olive stone flour: Mechanical, thermal, and water absorption properties

ABSTRACTThe production of olive oil leads to considerable amounts of solid waste mainly composed of hard woody endocarp called olive stones. The aim of this work is to explore the possible use of ground olive stones as fillers for polyvinyl chloride (PVC), to elaborate a cost‐effective composite material with a solid loading of up to 50 wt %. After grinding, the ensuing olive stone flour (OSF) was incorporated into a PVC matrix via melt compounding and injection molding to elaborate PVC‐OSF‐based composites with a filler content up to 50 wt %. The evolution of the mechanical performance, the impact property, the water absorbance, and wear resistance behavior, according to the OSF content, were investigated. The addition of OSF was shown to enhance the stiffness of the matrix, but at the expense of its mechanical strength. However, the strength of the composite did not fall as low as 30 MPa, and therefore, meets the requirements for many applications in plastic‐based materials. The thermal properties of the ensuing composites were also studied by thermogravimetric analysis. The results show that the addition of OSF may be effective in increasing the stiffness of the PVC‐based composite and in reducing the solid residue in the olive oil industry production. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 41083.

Thermal properties of poly( l-lactide)/olive stone flour composites

Thermal properties of poly( l-lactide)/olive stone flour (PLLA/OSF) composites were investigated by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) using dynamic heating regime. PLLA was blended with various amount of OSF using Brabender plastograph and pressed in a hydraulic hot press. DSC analysis showed that the glass transition temperature and the melting temperature of PLLA in the composites remained the same, while the cold crystallization temperature decreased. The crystallinity of PLLA was changed, too. SEM analysis confirmed weak interactions between polymer matrix and the filler. According to TG analysis, PLLA decomposes in one step, PLLA/OSF composites in two and OSF in three degradation steps. As the amount of OSF increases, thermal stability of PLLA decreases. At conversion higher than 0.7 char formation is probably responsible for higher E a values of nonisothermal degradation of PLLA composites compared to pure PLLA.